Indian homes currently rely on domestic reverse osmosis (RO) systems to desalinate groundwater to a salt content with total dissolved solids (TDS) that is suitable for drinking (less than 500 mg/L [1]). However, these systems are inefficient, recovering only 25-40% [2] of the feed, and thereby stressing limited groundwater resources. Given that the concentration of the groundwater underlying a majority of India is under 2000 mg/L, electrodialysis (ED) can provide a higher recovery and more energy-efficient desalination compared to RO [3,4].
While ED appears to be a promising alternative for domestic groundwater desalination, limited work has been performed to characterize the design of a system that is appropriate for the given application. Pilat has provided some information regarding his system, which was piloted before 2001 [5]; however, cost and design details are not provided. More recently, Thampy et al. investigated a hybrid approach whereby ED was used to initially desalinate 2000-4000 mg/L water to 500 mg/L, and further desalination to 120 mg/L or lower thereafter was achieved using RO [6]. However, their small-scale system did not implement recirculation of product water, thereby recovering only 50-60% of the feed.
There remains a need in the art for improved water desalination systems and methods including, for example, systems and methods capable of providing product water concentrations suitable for drinking, having high product recovery ratios, and/or of low cost to consumers.